The present invention relates to a process and an apparatus for continuously measuring the temperature deviation due to the superfusion or supercooling at the solidification front of a monocyrstal during dormation and has an interesting application in checking crystal growth, particularly checking the composition of a doped monocrystal during the formation therof.
Crystal growth form a molten bath is one of the most widely used methods for producing top quality metallic or semiconductor crystals.
The most sought properties are the crystalline quality and the homogeneity of the composition, which involves the checking of the doping or the distribution of the residual impurities. The most widely known crystal growth methods are the Czochralski pulling method, the Bridgman method, the horizontal or vertical Stockbarger method, the floating zone method and the zone melting method. However, at present, nore of these methods makes it possible to continuously follow the concentration of the crystal formed when the material is opaque (which is the case with metals and semiconductors when in the liquid state). Analyses are necessarily perforemd a posteriori by a distructive method, such as chemical or electrical analyses.
The object of the present invention is obviate these disadvantages by proposing a process and an apparatus making it possible to check the composition of a crystal during the formation thereof and without disturbing the same.